Idon’tbecomeaseriousclimberuntilthefifthgrade,

问题详情：

 I don’t become a serious climber until the fifth grade, ______ I went up to rescue a kite that was stuck

  in the branches of a tree.

   A. when                 B. where             C. which                D. why

【回答】

知识点：定语从句

题型：选择题